The IDC is a central element of the CTBT verification mechanism. It collects, processes and analyses monitoring data originating from the 337 facilities of the International Monitoring System (IMS). Processing and analysis results are then presented as lists of events, bulletins and reports to Member States. Based on this information, States are enabled to make judgements about an ambiguous event. The IDC also archives all data and data bulletins in its computer centre.

As a central element of the CTBT verification mechanism, the IDC
collects, processes and analyses monitoring data and presents
results as lists of events and bulletins to Member States.

Treaty negotiations on the IDC

While negotiating the functions of the IDC during the Conference on Disarmament in Geneva in the mid-nineties, it was recognized that IMS monitoring data would need to be processed and analysed by specialist staff. The level of detail at which data analysis would need to be carried out was, however, a major point of debate.

On one hand, it was clear that a large number of countries would not have the capacity or technical capability to conduct routine analysis of monitoring data.

Treaty negotiations on the IDC cont.

On the other hand, a smaller group of developed countries would be able to conduct their own data processing and analysis. A compromise was needed. Treaty negotiators agreed that the IDC would provide initial analysis and present States with basic parameters describing an event, such as location, magnitude and depth.

An important political concern was at the centre of discussions about IDC analysis. It was recognized that it should not be the task of the IDC to make a final judgement on the nature of a suspicious event, as this would amount to making a political assessment of a State’s compliance with the Treaty.

During Treaty negotiations, it was recognized that monitoring
data would need to be processed and analysed to provide
States with basic information describing an event.

This prerogative would be retained by Member States since it would be their responsibility to consider calling for an on-site inspection – if data and data analysis pointed to a possible Treaty violation. It was therefore agreed that the IDC would provide monitoring data and data bulletins to Member States, who would thus be enabled to make an informed judgement concerning an ambiguous event.

Negotiators agreed that it should not be the task of the IDC to make a final judgement on the nature of a suspicious event, but that Member States would retain this prerogative.

A group of scientific experts conducted three consecutive
experiments to test monitoring technologies and analysis
methods for the verification of a nuclear test ban. They set up
an experimental data centre, the PIDC, in Arlington, Virginia, USA.

The Prototype IDC

An initial prototype of the IDC existed before the CTBT was adopted. Why was that? To answer that question, we need to take a step back.

A group of international specialists, the Group of Scientific Experts (GSE), established at the Conference on Disarmament in Geneva, had been researching monitoring technologies and analysis methods for the verification of a nuclear test ban since 1976.

The Prototype IDC cont.

The GSE conducted three progressively more ambitious experiments to test their concepts. The first Group of Scientific Experts Technical Test, GSETT-1, in 1984, was an exchange of parameters between all participants. During GSETT-2 in 1991, selected waveform data were collected and exchanged between four globally distributed data centres in Australia, the Russian Federation, Sweden and the United States of America.

On 1 January 1995, a third test, GSETT-3, started to look into new concepts for a verification system based primarily on seismic monitoring. An experimental International Seismic Monitoring System was set up and complemented by an experimental data centre, the Prototype International Data Center (PIDC).

In the course of this test, the PIDC, which was located in Arlington, Virginia, USA, developed the initial software for the processing of seismic and hydroacoustic monitoring data. The outcome consisted of bulletins with detailed lists of detected and located events.

The IDC was established in Vienna in 1997 and first sent
processing and analysis bulletins to Member States in 1999.

Transfer to Vienna

Following the adoption of the Treaty and the formation of the Preparatory Commission for the Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO) in 1996, the data centre function moved to Vienna, Austria, the seat of the new organization. The process of transferring data and software to the newly created IDC of the CTBTO began in 1997.

During the transition period, the two data centres worked in parallel. In 1998, the IDC created its first data products and a year later, in 1999, the first processing and analysis products were sent to Member States.

In February 2000, Member States decided that the IDC was now capable of starting routine and independent data analysis and product distribution. The role of the PIDC in establishing the CTBTO’s IDC was fulfilled and, after more than five years, GSETT-3 came to a successful closure.